Typically, in construction of commercial, industrial and some residential space, building codes require the use of metal conduit, for holding electrical wires, which terminate at an electrical junction box. A variety of electrical switches and receptacles can be mounted on a Mud Ring inside the junction box. The conduit and junction boxes are mounted within the walls of the building and the Mud Rings is attached to the junction box. The Mud Ring should extend through an opening in the wall and be flush to the exterior surface of the wall, the switch or receptacle is connected to the Mud Ring, the electrical fixture extends through the wall opening and a cover plate is normally attached to the exterior of the wall, hiding electrical connections.
A problem often encountered is that, because the junction box assembly is normally installed prior to the installation of the wall surface materials, it is sometimes difficult to estimate the proper position of the Mud Ring. Further, if the exterior surface of the wall is changed from the original specifications, the yoke of the switch or receptacle may no longer be seated securely on the Mud Ring for proper grounding while still keeping flush with the wall.
While prior attempts to deal with this problem have been made, each has problems associated with the design or is costly. Among these are U.S. Pat. Nos. 5,931,325, 6,765,146, 6,820,760, 6,953,894, and 7,038,131. Some systems require a special junction box, while others provide telescoping adaptors that limit the size of acceptable switches and receptacles. Other systems require a collar be present on the Mud ring which limits the travel of the telescoping adapter into the junction box. Others do not have a secure means for attachment of the extending member, allowing for movement and incomplete grounding. None of the systems allow for multiple extending members that are equipped with some of the thicker surface finish materials currently being used in the industry.
The present invention relates to a system which allows for the use of a conventional junction box, such as a 4S, 11/16, Three Gang, Four Gang, Five Gang, Six Gang, Seven Gang Eight Gang, Nine Gang or Ten Gang box. This saves cost when the finish surface material on a wall is changed to a thicker material because it allows for the use of the currently installed junction box with the present invention to secure the junction box to the new, thicker finish surface material. Further, the present invention features a collarless Mud ring which allows for maximum interior space inside the box for acceptance of larger switches or receptacles and maximum travel into the junction box itself. Through the use of bendable tabs, the invention provides more secure attachment of the extending members and a continuous ground of the system. Bendable tabs on the Mud Ring frame provide constant contact between the frame and the Extending Member for proper grounding, while also preventing the Extending Member from rocking. Bendable tabs on the extending members provide for firm attachment of the extending member to the exterior wall surface. The system also allows for Add-On Rings, which are additional Extending Members, to provide for additional telescoping beyond the range of the a single Extending Member when it is fully extended. The Add-On Rings have tabs which create a flat surface connection to ensure proper grounding between the Add-On ring and the Extending Member. The tabs also allow for installation of unlimited additional Add-on Rings, to accommodate varying thicknesses of the exterior wall schedules. The system also provides for an improved ground connection for the electrical switch or receptable through the use of a Grounding Spring Clip. Finally, the present invention may be modified to include a bracket on the Mud Ring for attaching the Mud Ring to wall studs. This provides improved stability for the entire assembly.